HVAC (Heating Ventilation and Air Conditioning) systems are used for climate control of, e.g., internal cabin areas of an automobile. HVAC systems may be configured with an HVAC unit having a heat exchanger disposed in a housing. An HVAC distribution system may be operatively connected to the HVAC unit. An HVAC system may have one or more air flow paths for allowing air to flow, for example, to, from, and/or within the HVAC unit and the HVAC distribution system. Doors may be associated with the air flow path for controlling the amount of air flowing to, through, and/or from the HVAC unit and/or the HVAC distribution system.
Some HVAC units have a housing made by assembling two injection molded plastic housing pieces. The injection molded plastic housing pieces must mate in accordance with close tolerance geometry. The process by which the housings are cooled when they exit the injection mold die significantly influences the warping of the housing pieces. Some HVAC housings are made by molding the mating housing pieces simultaneously, and then immediately following the mold process, putting the hot mating pieces together so that they cool with mating features engaged, thereby preventing the mating features from hardening out of shape. After the housing pieces cool, the mating pieces are separated for installation of components like an evaporator, heater core, blend doors, etc. After the components are installed, the housing pieces are once again mated together and fastened.